#include <stdio.h>
int main(){
  int score;
  scanf("%d", &score);
  if (score < 0 || score > 100)
    puts("Are you kidding!");
  else if (score >= 90){
    puts("A");
    printf("your score=%d!\n", score);
  }
  else if (score >= 80)
    puts("B");
  else if (score >= 70)
    puts("C");
  else if (score >= 60)
    puts("D");
  else
    puts("E");
}
